Blocky tread, yellow hub-- yep, it looks like LEGO

10″ LEGO Tyre Is Practical Nostalgia

If there’s one thing that has come to define the generations after the baby boom, it’s probably nostalgia. It’s heavily marketed and weaponized by the market: yearning for better, simpler times seems to be a core thread of the consumer economy these days. [Makerneer] combined his xilennial love of LEGO bricks with the flat tires on his log splitter to produce a 10″ TPU tyre will never go flat, and provide a dopamine release every time he sees it.

The tyre is a custom model to fit his particular rims, but he does provide STEP and F3D files if you’d like to try modifing it for your own purpose — they’re at Step 6 of the Instructable. Props to [Makerneer] for truly open-sourcing the design instead of just tossing STL files online. His build log also takes the time to point out the ways he had to modify the LEGO tyre profile to make it amenable to 3D printing: notably chamfering some of the tread pattern to eliminate bridging, which is a bit of a no-no with TPU.

As you can see in the (unfortunately vertical) demo video below, it’s a bit quite a bit squishier than a regular run-flat tyre, but that was part of [Makerneer]’s design goal. He didn’t like how rigid the non-pneumatic tyres he’d tried were, so endevoured to design something himself; the whole LEGO thing was just for fun. If you wanted to replicate this tyre with a bit less skoosh, you need only tune the infill on your print.

While only time will tell how long this LEGO-inspired add-on will continue adding whimsy to [Makerneer]’s log-splitting, we have tests to show it will outperform any other plastic he might have printed. This project is probably more practical than a 3D printed bicycle tyre, which doesn’t even have the side benefit of whimsy. Continue reading “10″ LEGO Tyre Is Practical Nostalgia”

Elegoo Rapid PETG Vs PETG Pro: Same Price, Similar Specs, Which To Buy?

Even within a single type of FDM filament there is an overwhelming amount of choice. Take for example Elegoo’s PETG filament offerings, which include such varieties like ‘Pro’ and ‘Rapid’. Both cost the same, but is there a reason to prefer one over the other, perhaps even just for specific applications? To test this, [Dr. Igor Gaspar] over at the My Tech Fun YouTube channel bought some spools of these two filaments and subjected both to a series of tests.

Obviously, the Rapid filament is rated for higher extrusion speeds – <270 vs <600 mm/s – while the website claims a higher required nozzle temperature that confusingly does not match those listed on the spool. There are quite a few differences in the listed specifications, including the physical and mechanical properties, which make it hard to draw any immediate conclusions. Could you perhaps just use Rapid PETG and forget about the Pro version?

Test objects were printed with a Bambu Lab P1P with an AMS unit. After calibrating the ideal temperature for each filament, a tensile break test gave a win to the Rapid PETG, followed by a layer adhesion test win. This pattern continued across further tests, with Rapid PETG either matching or beating the Pro PETG.

There are only two advantages of the Pro version that can be seen here, which are less moisture sensitivity and  stringing risk, and you of course get the luxury cardboard spool with the closed edges. Whether that’s enough to make you go ‘Pro’ remains to be seen, of course.

Continue reading “Elegoo Rapid PETG Vs PETG Pro: Same Price, Similar Specs, Which To Buy?”

There Are Better Lego-Compatible Universal Joints Out There

Lego’s Technic line features all kinds of mechanical devices, from cogs to gears to chains and even pneumatic components. However, the vast majority of these components are made out of plastic and are only capable of toy-like levels of performance. In the competitive world of Lego YouTube, builders often push these parts to their limits, breaking them more often than you might think. To that end, [Brick Experiment Channel] has been investigating stouter Lego-compatible universal joints from a variety of third-party manufacturers.

The video starts with a simple demonstration, showing that a Lego universal joint pops apart at just 0.4 Nm of torque. It’s no surprise, given it relies on tiny plastic pins in snap-fit joints. However, this means that it’s not that hard to build a stronger universal joint to outperform the stock parts.

The video steps through a range of other options available on the market. For example, CaDA builds a universal joint using aluminium sleeves, a copper center, and steel pins to join everything together. It’s so strong that the plastic Lego axles fail long before the joint does. Tested with third-party aluminum axles, it eventually fails at 2.3 Nm of torque when the aluminum sleeve snaps. An all-steel joint from MTP goes even harder, eventually stripping out its axle mount at 4 Nm. The rest of the video goes on to explore angular performance, size, and other design features.

It’s fair to say that if you’re swapping out universal joints and axles for aluminum steel parts, you’re not really playing with Lego anymore. At the same time, it’s neat that there exists a sort of defacto standard kit for mechanical experimentation that is now being expanded upon with stronger components. Video after the break.

Continue reading “There Are Better Lego-Compatible Universal Joints Out There”

Mechanical 7-Segment Display Combines Servos And Lego

If you need a seven-segment display for a project, you could just grab some LED units off the shelf. Or you could build something big and electromechanical out of Lego. That’s precisely what [upir] did, with attractive results.

The build relies on Lego Technic parts, with numbers displayed by pushing small black axles through a large yellow faceplate. This creates a clear and easy to read display thanks to the high contrast. Each segment is made up of seven axles that move as a single unit, driven by a gear rack to extend and retract as needed. By extending and retracting the various segments in turn, it’s possible to display all the usual figures you’d expect of a seven-segment design.

It’s worth noting, though, that not everything in this build is Lego. The motors that drive the segments back and forth are third-party components. They’re Geekservo motors, which basically act as Lego-mountable servos you can drive with the electronics of your choice. They’re paired with an eight-channel servo driver board which controls each segment individually. Ideally, though, we’d see this display paired with a microcontroller for more flexibility. [upir] leaves that as an exercise for the viewer for now, with future plans to drive it with an Arduino Uno.

Design files are on Github for the curious. We’ve featured some similar work before, too, because you really can build anything out of Lego. Video after the break.

Continue reading “Mechanical 7-Segment Display Combines Servos And Lego”

A Lego vehicle crossing a gap between two benches.

Making A LEGO Vehicle Which Can Cross Large Gaps

Here is a hacker showing off their engineering chops. This video shows successive design iterations for a LEGO vehicle which can cross increasingly large gaps.

At the time of writing this video from [Brick Experiment Channel] has been seen more than 110,000,000 times, which is… rather a lot. We guess with a view count like that there is a fairly good chance that many of our readers have already seen this video, but this is the sort of video one could happily watch twice.

Continue reading “Making A LEGO Vehicle Which Can Cross Large Gaps”

Reverse Engineering LEGO Island

While LEGO themed video games have become something of a staple, in 1997 they were something of an odity. LEGO Island became the first LEGO video game released outside of Japan in 1997 and become something of a hit with over one million copies sold. The game was beloved among fans and set the stage for more LEGO video games to come. In an effort of love, [MattKC] put together a team to reverse engineer the game.

The team set out with the intent to create a near perfect recreation of the codebase, relying on custom made tools to run byte checks on the rewrite compilation and the original binary. While the project is functionally complete, [MattKC] believes it is impossible to get a byte accurate codebase. This is because of what the team called “compiler entropy.” Strange behaviors exists inside of Microsoft’s Visual C++ compiler of the era, and small changes in the code have seemingly random effects to unrelated parts of the binary. To mitigate this issue would likely require either partially reverse engineering Visual C++ or brute forcing the code, both of which would take a large amount of effort and time for no real benefit.

Continue reading “Reverse Engineering LEGO Island”

Welcome Your New AI (LEGO) Overlord

You’d think a paper from a science team from Carnegie Mellon would be short on fun. But the team behind LegoGPT would prove you wrong. The system allows you to enter prompt text and produce physically stable LEGO models. They’ve done more than just a paper. You can find a GitHub repo and a running demo, too.

The authors note that the automated generation of 3D shapes has been done. However, incorporating real physics constraints and planning the resulting shape in LEGO-sized chunks is the real topic of interest. The actual project is a set of training data that can transform text to shapes. The real work is done using one of the LLaMA models. The training involved converting Lego designs into tokens, just like a chatbot converts words into tokens.

There are a lot of parts involved in the creation of the designs. They convert meshes to LEGO in one step using 1×1, 1×2, 1×4, 1×6, 1×8, 2×2, 2×4, and 2×6 bricks. Then they evaluate the stability of the design. Finally, they render an image and ask GPT-4o to produce captions to go with the image.

The most interesting example is when they feed robot arms the designs and let them make the resulting design. From text to LEGO with no human intervention! Sounds like something from a bad movie.

We wonder if they added the more advanced LEGO sets, if we could ask for our own Turing machine?